Multivariate approach
Multivariate approach utilizes techniques to determine the effects of many (more than two) variables in a study. This uses multivariate statistical techniques, often involving high level mathematics.
The multivariate approach is especially useful in the field of social science research where it is generally difficult or impossible to use randomized laboratory experiments, very often used in medicine and natural sciences. Multivariate analysis then helps establish relationships between different variables and provide correlations on the importance of the different variables and their interactions with one another to the outcome.
Cattell used this approach to produce highly specific data in his study of the structure of personality.